[PATCH v3 04/10] KVM: MMU: introduce for_each_slot_rmap_range

Xiao Guangrong
2015-05-13T06:46:14Z

It's used to abstract the code from kvm_handle_hva_range and it will be
used by later patch

Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
---
arch/x86/kvm/mmu.c | 97 +++++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 75 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index e0e15b8..df403b3 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1412,6 +1412,74 @@ restart:
return 0;
}

+struct slot_rmap_walk_iterator {
+ /* input fields. */
+ struct kvm_memory_slot *slot;
+ gfn_t start_gfn;
+ gfn_t end_gfn;
+ int start_level;
+ int end_level;
+
+ /* output fields. */
+ gfn_t gfn;
+ unsigned long *rmap;
+ int level;
+
+ /* private field. */
+ unsigned long *end_rmap;
+};
+
+static void
+rmap_walk_init_level(struct slot_rmap_walk_iterator *iterator, int level)
+{
+ iterator->level = level;
+ iterator->gfn = iterator->start_gfn;
+ iterator->rmap = __gfn_to_rmap(iterator->gfn, level, iterator->slot);
+ iterator->end_rmap = __gfn_to_rmap(iterator->end_gfn, level,
+ iterator->slot);
+}
+
+static void
+slot_rmap_walk_init(struct slot_rmap_walk_iterator *iterator,
+ struct kvm_memory_slot *slot, int start_level,
+ int end_level, gfn_t start_gfn, gfn_t end_gfn)
+{
+ iterator->slot = slot;
+ iterator->start_level = start_level;
+ iterator->end_level = end_level;
+ iterator->start_gfn = start_gfn;
+ iterator->end_gfn = end_gfn;
+
+ rmap_walk_init_level(iterator, iterator->start_level);
+}
+
+static bool slot_rmap_walk_okay(struct slot_rmap_walk_iterator *iterator)
+{
+ return !!iterator->rmap;
+}
+
+static void slot_rmap_walk_next(struct slot_rmap_walk_iterator *iterator)
+{
+ if (++iterator->rmap <= iterator->end_rmap) {
+ iterator->gfn += (1UL << KVM_HPAGE_GFN_SHIFT(iterator->level));
+ return;
+ }
+
+ if (++iterator->level > iterator->end_level) {
+ iterator->rmap = NULL;
+ return;
+ }
+
+ rmap_walk_init_level(iterator, iterator->level);
+}
+
+#define for_each_slot_rmap_range(_slot_, _start_level_, _end_level_, \
+ _start_gfn, _end_gfn, _iter_) \
+ for (slot_rmap_walk_init(_iter_, _slot_, _start_level_, \
+ _end_level_, _start_gfn, _end_gfn); \
+ slot_rmap_walk_okay(_iter_); \
+ slot_rmap_walk_next(_iter_))
+
static int kvm_handle_hva_range(struct kvm *kvm,
unsigned long start,
unsigned long end,
@@ -1423,10 +1491,10 @@ static int kvm_handle_hva_range(struct kvm *kvm,
int level,
unsigned long data))
{
- int j;
- int ret = 0;
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
+ struct slot_rmap_walk_iterator iterator;
+ int ret = 0;

slots = kvm_memslots(kvm);

@@ -1446,26 +1514,11 @@ static int kvm_handle_hva_range(struct kvm *kvm,
gfn_start = hva_to_gfn_memslot(hva_start, memslot);
gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);

- for (j = PT_PAGE_TABLE_LEVEL;
- j <= PT_MAX_HUGEPAGE_LEVEL; ++j) {
- unsigned long idx, idx_end;
- unsigned long *rmapp;
- gfn_t gfn = gfn_start;
-
- /*
- * {idx(page_j) | page_j intersects with
- * [hva_start, hva_end)} = {idx, idx+1, ..., idx_end}.
- */
- idx = gfn_to_index(gfn_start, memslot->base_gfn, j);
- idx_end = gfn_to_index(gfn_end - 1, memslot->base_gfn, j);
-
- rmapp = __gfn_to_rmap(gfn_start, j, memslot);
-
- for (; idx <= idx_end;
- ++idx, gfn += (1UL << KVM_HPAGE_GFN_SHIFT(j)))
- ret |= handler(kvm, rmapp++, memslot,
- gfn, j, data);
- }
+ for_each_slot_rmap_range(memslot, PT_PAGE_TABLE_LEVEL,
+ PT_MAX_HUGEPAGE_LEVEL, gfn_start, gfn_end - 1,
+ &iterator)
+ ret |= handler(kvm, iterator.rmap, memslot,
+ iterator.gfn, iterator.level, data);
}

return ret;
--
2.1.0